Genealogy / Best DNA Test Kits

Best DNA Test Kits

How to Choose the DNA Testing Kit That’s Best for You
Marc McDermott

If you’ve read all the DNA test reviews, and are still confused, read on. What is the best DNA test? This guide will break down everything you need to know. But first, here’s a quick comparison:

Comparison of important features

AncestryDNA MyHeritage FamilyTree DNA 23andMe LivingDNA
Website Ancestry.com MyHeritage.com FamilyTreeDNA.com 23andMe.com LivingDNA.com
Best for Genealogy, matches, ethnicity regions Global matches, tools for advanced genetic genealogy Distant ancestry, YDNA, mtDNA Genetic health testing British Isles ancestry
Price See latest price
See latest price
See latest price
See latest price
See latest price
Ethnicity results Yes Yes Yes Yes Yes
Ethnic Regions 1,000+ 42 24 1,000+ 80 (in depth for UK)
Family Matching Yes Yes Yes Yes Limited
Database Size 18 million 3.8 million 1 million 10 million None
Y-DNA Test No No Yes Broad haplogroup, no matching Broad haplogroup, no matching
mtDNA Test No No Yes Broad haplogroup, no matching Broad haplogroup, no matching
Collection Method Saliva Cheek swab Cheek swab Saliva Cheek swab
Chromosome Browser No Yes Yes Yes No
Raw Data Upload No Yes Yes No Yes
Health Info For extra fee For extra fee No For extra fee No

DNA testing reviews

AncestryDNA

The best test kit for genealogy, AncestryDNA has the most extensive database (18 million customers) so you’ll find the most DNA matches there.

Ancestry DNA test kit

What we like:

  • Database of over 18 million customers for matching
  • Strong genealogical community
  • Connect with matches through anonymous email and message boards
  • Link your DNA results to your online family tree
  • No subscription required

What we don’t like

  • Viewing family trees of your matches requires a subscription
  • Does not allow raw data uploads from other sites

Read our complete AncestryDNA review.

Note that you do not have to have an Ancestry subscription in order to take their test or see your results. You also do not need a subscription to build your own family tree.

A subscription allows you to view genealogical records, view the family tree’s of your matches, and compare your tree with your match to find common ancestors.

There are of course many other features on the research side of your genealogy. Get a 14-day free trial here.

MyHeritage DNA

The best DNA test kit if you’re looking for matches outside the United States, MyHeritage has the largest database of international customers. They also offer some pretty neat tools such as auto clustering and a chromosome browser.

MyHeritage test kit

What we like:

  • Largest database of international customers to be matched with
  • Link your DNA results to your online family tree
  • Allows free upload of raw data from other sites
  • Covers 42 ethnic regions
  • The price. Usually more affordable than the competition.

What we don’t like

  • Relatively small (but rapidly growing) database compared to other sites. Currently 3.8 million

Read our complete MyHeritageDNA review.

23andMe

23andMe is the best test kit for dedicated genetic testing for health. Since most people who test there aren’t as interested in family history or communicating with DNA matches as compared to sites like Ancestry, 23andMe would probably not be my first choice for genealogy. The health test gives you reports for carrier status, health risks, traits, and wellness.

23 and me DNA test kit

What we like:

  • The best company for health and wellness reports
  • Has a large database of more than 10 million customers
  • Includes a chromosome browser for comparing results

What we don’t like

  • Very limited genealogical community compared to other sites
  • No Y-DNA or mtDNA matching
  • Does not allow upload of raw data from other sites

Read our complete 23andMe review.

You may also be interested in our complete comparison of 23andMe vs Ancestry.

FamilyTreeDNA

The best for distant ancestry (beyond 6-8 generations), and paternity testing. One major perk is, even if you do get your testing done by a different company, FamilyTreeDNA lets you upload your raw data into their system as well.

FamilyTreeDNA

What we like:

  • Only company to offer all three tests separately
  • Only company to offer Y-DNA and mtDNA matching
  • Cheek swab DNA collection (much easier for babies and elderly)
  • Allows free upload of raw data from tests run for other sites
  • Has a chromosome browser, which lets you compare two or more sets of DNA results to see segment overlap
  • Surname, haplogroup and other group projects you can join

What we don’t like

  • Has a smaller database of people than sites like Ancestry (since it’s not as popular to the mass market), so you might miss some matches
  • Very broad ethnicity regions

Read our complete FamilyTreeDNA review.

Living DNA

If you have any British or Irish ancestry, you’ll definitely want to do an ancestry test with LivingDNA. Based in the UK, LivingDNA specializes in “high definition” genetic testing in the British Isles and can narrow into the exact regions of your ancestry in the British Isles.

Because of the lack of a customer database (and matches), I would also test with another company in addition to LivingDNA.

LivingDNA

What we like:

  • Divides the UK and Ireland into many more, smaller regions than other services

What we don’t like

  • No separate autosomal DNA only test, so highest overall price
  • Almost no database for matches

Read our complete LivingDNA review.

Buyer’s guide

In this guide:

Types of DNA tests

There are three main types of DNA tests used in genealogy.

Each one works a little differently, and tells you different things.

Naturally, that means that each one has its advantages and disadvantages.

Autosomal DNA tests (atDNA)

autosomal DNA inheritance chart
Autosomal tests are the most popular and look at the DNA you inherited from every line in your family tree. This test provides an estimate of your ethnicity – or the regions of the world where your ancestors lived within the past few hundred years. This test also matches you with distant relatives.

Autosomal DNA (atDNA) is that DNA that does not contribute to gender; in other words, the first 22 pairs of chromosomes. It is inherited from both your maternal and paternal ancestors.

Because it does not rely on the 23rd chromosome, atDNA tests can be done in both men and women with the same results.

What is an atDNA test?

atDNA tests are by far the most popular for consumers. This is the test that gives you ethnicity estimates as well as family matches.

This test examines single-nucleotide polymorphisms (SNPs), or the different “shapes” of individual nucleotides, small chunks of DNA.

Genealogical atDNA tests examine about 700,000 SNPs to determine how closely related you are to someone else.

Remember that half our DNA comes from our father and half from our mother.

Going back in generations, that means that roughly one-fourth of our DNA comes from each of our grandparents, one-eighth from each of our great-grandparents, and so on. These percentages are never exact since DNA inheritance and recombination is completely random.

The further you go back, the less DNA you have inherited from a particular ancestor, and the harder it is to prove that you are related.

So atDNA tests are only useful for about 6-8 generations.

What It Tells You

Most people who do an autosomal test do so for ethnicity estimates. Autosomal tests will give you a set of ethnicity results based on how your DNA compares to reference populations created by the testing company.

For genealogical purposes, the main use of atDNA testing is to find relatives and determine how closely related you are to someone else.

This can be especially useful if you know very little about your parents or grandparents and are having a hard time locating living relatives.

Many times, relatives located by the test are researching the same family lines as you, and you can share research with them.

Every company mentioned in this guide offers autosomal tests. Again, it is by far the most popular test for consumers.

Mitochondrial DNA testing (mtDNA)

mitochondrial dna inheritance
Mitochondrial DNA (mtDNA) is passed down from a mother to all her children (both male and female) and examines your direct maternal line only. Like Y-DNA, mtDNA changes very slowly over time so you can trace maternal lines back thousands of years. This test should not be confused with X-DNA analysis.

mtDNA is genetic material inside mitochondria, small components found inside every cell and which have their own separate DNA strands.

mtDNA is passed down exclusively from females. Both males and females inherit their mtDNA from their mothers, therefore anyone can take this test.

Because mtDNA does not include a combination of DNA from both parents, it does not change with every generation.

In fact, mtDNA changes extremely slowly – it might remain exactly the same for dozens of generations!

How It Works

While atDNA testing looks at the 22 pairs of autosomes inside the cell nucleus, mtDNA testing looks at the DNA inside the mitochondria which exists outside the cell nucleus.

Among other things, that means the test only has to examine about 16,500 genetic base pairs, instead of the 3.2 billion base pairs found in our DNA.

The test normally looks at only specific portions of the mtDNA and compares them to established samples.

What It Tells You

mtDNA gives very precise and accurate ancestry results, but only for the maternal line.

results, but only for the maternal line.

That is, it tells you about your mother’s mother’s mother’s mother, and so on, back through time.

But it can’t tell you about any of your other ancestors, such as your mother’s father or any of your father’s ancestors.

An mtDNA test will also identify how closely related you are to a haplogroup.

A haplogroup is basically a group of people with a single common ancestor.

Historically, everyone living in the same region might belong to the same haplogroup, or very closely related ones.

This means that your haplogroup can identify where your maternal line originated.

It could also help you locate distant relatives, but some of them could be very distant (thousands of years).

In some cases, mtDNA can remain nearly identical for 50 generations or more. This makes it difficult to use mtDNA matching for genealogical purposes. A perfect match means you are related, but you might be 48th cousins!

The only company to offer individual mtDNA kits is FamilyTreeDNALiving DNA  and 23andMe bundle very basic mtDNA testing with their atDNA test.

Y-DNA tests

Y-DNA inheritance
Y-DNA Tests look at the Y-chromosome (only found in males) which is passed from father to son and changes very little over time. This allows you to trace the direct line back thousands of years. Females don’t have a Y-chromosome so they cannot take this test. However, they can ask a male relative (i.e. brother, father, uncle, etc.) to take the test for them.

The 23rd human chromosome has two versions, the X and the Y.

Women have two X-chromosomes, while men have one X and one Y.

Y-DNA testing kits examine only the Y-chromosome, therefore only males can take this test. If you’re a woman who wants to test your father’s Y-DNA male line, you’ll need to test your father, uncle, brother, male cousin, etc. Basically any male on your direct paternal line. Testing the oldest generation possible is always best.

Because you can only get a Y-chromosome from your father, and he from his father, that means it tends to change very little over time.

How It Works

There are actually two sub-tests with Y-DNA testing.

The first is a short tandem repeat (STR) test. The STR test categorizes sections of the DNA according to how often a certain genetic pattern repeats.

The second is a single-nucleotide polymorphism (SNP) test. It works the same way as in atDNA testing, but it only tests about 30,000 SNPs instead of 700,000.

What It Tells You

The STR test produces a summary of your haplotype. This can be compared to someone else’s results to determine how far back your most recent common ancestor might have lived.

An STR test is often used to determine how closely two people with the same surname are related, if at all.

The SNP test is more detailed, and among other things assigns you to a haplogroup.

A haplogroup is a group of people with one common ancestor and who lived in one or more specific regions.

Both Y-chromosome tests can help you locate relatives.

But like mtDNA, because the Y-chromosome changes slowly, you might be related many generations back. Although Y-DNA is much more useful for genealogy than mtDNA.

And because the Y-chromosome is only passed down through males, the test can only tell you about your direct paternal line.

The only company to offer individual Y-DNA testing kits is FamilyTreeDNA, which has three options depending on how detailed a test you want.

Y-DNA testing is especially useful for adoptees. It’s also a great ancestry test if you think you have jewish ancestry.

Living DNA and 23andMe bundles very basic Y-DNA testing with their atDNA tests, but provide much less detailed results than FamilyTreeDNA.

Choosing the test that’s best for you

With three tests to choose from, how do you decide which is best for you?

It all depends on what you want to know.

Autosomal

For most people, the atDNA test is the clear winner, and it is the one test that every testing company offers.

Because your atDNA comes from all of your ancestors, this test is good for finding a range of ancestors and living relatives.

It can also provide you with reasonable estimates of the ethnicity of your ancestors, or the regions of the world where they lived.

The main drawback to atDNA is that it gets so jumbled together after a few generations that it becomes unreliable the further you try to go back.

Most of the time, an atDNA test is only useful for about 6-8 generations.

atDNA can provide some great leads on finding others who are researching the same family tree as you.

mtDNA

Because mtDNA comes to you only from your mother, and from her mother, it only helps you trace one line.

You can use it to prove a common ancestor with someone else, but only in a direct maternal line.

It can, however, trace that line back a very long way – sometimes 10,000 years or more.

That can provide evidence that your mother’s maternal line came from a very specific region or ethnicity.

But it is less useful when finding living relatives.

Y-DNA

The Y-DNA test is sort of like the mtDNA test, but it follows a direct paternal line instead.

That means a Y-DNA test can tell you about your father’s father’s father’s father, and many generations before that, but not about any of your other ancestors.

Y-DNA is most useful if you want to prove a connection to a certain ancestor.

Say that you have a common surname, like Smith, and want to know if you are related to someone else named Smith.

A Y-DNA can prove (or disprove) that the two of you are related.

Like the mtDNA test, Y-DNA may let you trace a line back for dozens of generations.

It can also tell you the ethnicity or region of origin of your paternal line.

One major drawback to a Y-DNA test is that only males have Y-DNA, so only males can take the test.

However, a woman can still find Y-DNA results by having a close male relative take it for her, such as her brother, father, paternal uncle, or cousin by a paternal uncle (but not her son, since he got his Y-chromosome from his paternal line, not hers).

In the same way, you can trace other paternal lines by asking an appropriate family member to take the test and share the results with you.

Ethnicity testing

All three of the tests can provide you with information on where your ancestors lived.

But the information they provide varies from test to test.

  • Y-DNA and mtDNA tests will link you to very specific genetic lines, but keep in mind, they represent only a fraction of your family tree.
  • atDNA testing is what’s used for ethnicity testing of your entire family tree.

The companies that provide DNA testing divide the world up into regions in different ways. Each company has different ways of doing this.

That means that two different testing companies may give you different ethnicity estimates for the exact same DNA.

As more and more genetic data is collected, companies update their regions, too.

Some companies have had problems with their ethnicity estimates in the past. AncestryDNA, for example, used to be well-known for overestimating Scandinavian ancestry.

But the accuracy of estimates is constantly improving as more genetic data are collected, and there’s no clear indication that one company is more accurate than the others.

When a company does improve its ethnicity estimates, your profile will automatically be updated, too. You won’t have to retake the test to get the new results, but you will have to visit their site. Chances are they will not email you with the update.

Regions versus countries

It’s important to keep in mind that any DNA test will typically give a region of origin, not a country.

That’s because countries have changed many times throughout human history, and even within your lifetime!

Consider the case of Alsace-Lorraine, a 5,600 square mile region on the border of France and Germany.

Before the 17th century, the area was entirely Germanic (even though Germany as a country didn’t exist at the time).

During the 17th and 18th centuries, it was annexed by France.

In 1871, following the Franco-Prussian War, it was annexed by Germany.

Following World War I, it was returned to France.

So how can you say if your ancestors from that area were German or French using only DNA?

You can’t.

You can only say that your ancestors came from that region.

And because of all the migration and intermarrying across borders, the results you get aren’t going to be that specific, anyway.

Chances are they’ll bundle Germany and France together, and simply tell you those ancestors came from continental western Europe.

Native American ancestry

​Can DNA testing determine Native American ancestry?

Many people in the United States want to know if they have any Native American ancestry, and if so, from what tribes.

The good news is DNA testing can, in some cases, tell you if you have Native American ancestors.

Read our full guide to testing for Native American ancestry.

Which test is best for you?

It depends on your goals…

Is it worth it?

So is genealogical DNA testing right for you?

In the end, is it really worth the cost and bother?

Absolutely.

Even if genealogy is only an occasional hobby for you, these tests can provide you with some very enlightening insights into your family history.

And for the serious genealogist, it is getting to the point where they are nearly essential.

Genealogical DNA testing is finally accurate enough, inexpensive enough, and useful enough for connecting with your family. I recommend it to everyone interested in learning more about their roots.

External references & citations

About the Author

Comments (839)

  1. Carol B

    Which Y-DNA test would be best to take?
    Family lore has always been that John Broady, who was at The Battle of Kings Mountain with his master, General William Campbell, in Oct 1780, is my significant other’s 4th or 6th great grandfather (depending on what family tree you believe). Because John Broady was General William Campbell’s man servant, he is mentioned in many books. It is also mentioned in some of these books that many thought John Broady was a half brother to General William Campbell. What Y-DNA test would be best for my significant other (last name Broady) to take to try and confirm his Broady lineage??? [He has taken an Ancestry DNA test and his results have been uploaded to Gedmatch.]
    Thank you, in advance, for any input you can provide.

    • Marc McDermott

      Hi Carol. For Y-DNA, I recommend starting with 37 markers. Then if there are some close matches who have tested at higher levels such as 67 or 111, you can upgrade your test without having to retake the test. But for what you’re asking, you’d need to match a known descendant of Gen. Campbell on the paternal line. And Broady would have to be the surname of your significant other – meaning John Broady is on his direct paternal line. So I would go ahead and test, but expect that you’ll likely have to do some genealogy research once you get your results.

  2. Charles Daniels

    Hello Marc,
    Thank you for the informative article. Question… I have already taken the AncestryDNA test, and want to know where my male line and Surname came from. I was always told we were Irish, and I know that some of my family… Great grandparents on up immigrated from Canada (FR) to the states. But, my results are 43% French, 14% Ireland and Scotland, and 1% England, Wales, & Northwest Europe.
    What test should I get to better know exactly where my male line came from… Ireland,Scotland,France, or England.
    Thank you in advance.
    And once again great article.
    Sincerely,
    Charles

    • Marc McDermott

      Hey Charles. For your direct paternal line, you can do a Y-DNA test at FamilyTreeDNA. The 37 marker test should be fine. You can also do another autosomal test with 23andMe because they report on broad Y-DNA haplogroups.

  3. LeAnn

    Hi Marc- I greatly appreciate the comparisons!!! Please can you provide your expert recommendation on which test(s) would be best for my elderly mother that is best suited for a cheek swab? She is the matriarch from very old colonial American lineages (British, Mayflower, Virginia, North Carolina). Can any produced DNA results be uploaded into Ancestry where I have my tree? She has a hard time spitting into the small tube for the saliva test. Thanks again!

    • Marc McDermott

      Hi LeAnn. I would likely test with MyHeritage since Ancestry only collects saliva. If you REALLY wanted to test with Ancestry, you can try this method: http://anotherteenmom.com/reviews/how-to-do-an-ancestrydna-test-without-spit/. Note that I have not done this myself so I don’t know how effective it is. I’ve read that some folks have had success though. Best of luck.

  4. Sandra Ridgeway

    Good Afternoon –

    How would I go about finding out my father’s biological family. I believe his adoption was a closed one. My father has passed so has his adoptive parents. Which DNA testing do I need to do?
    Thank you,
    Sandy

    • Marc McDermott

      You’d want to test with as many companies as possible to have the greatest chance of finding close matches. From there, you need to do a bit of genealogy research. Or you can hire a genealogist who specializes in adoption. But the first step is to get your DNA tested. Go with Ancestry then upload the raw data to MyHeritage, FTDNA, LivingDNA and Gedmatch.

  5. mary

    Hello! I have never met my biological father. I do know he is deceased. I know his name. My mother is deceased. I have a half brother with the same mother. I would like to find information regarding my fathers side; is that possible? What test would give the most information? I have some health issues that my mother did not have and im wondering if it is genetic on fathers side. I have a son who I would like to give the information to as well. Thank you

    • Marc McDermott

      Hi Mary. If you’re looking for a health test, try 23andMe or AncestryHealth.

  6. T.K.

    Thanks a lot for a very good intro to this matter! Ended up choosing 23andme for genetic health markers.

    I was wondering if you have had a possibility to look at any of the full sequencing tests offered? I just recently run into an offer from Dante Labs, and was thinking how they would compare.

    • Marc McDermott

      I have not yet but plan to look into it.

  7. Nicola Bowie

    Hi Marc
    I am an English woman living in the US for the past 18 years. My father was Scottish and we have quite a bit of information about his side of the family. My Mother was illegitimate and we know nothing about her other than the town she was born in in England and her Mother’s first name. I did a CRI genetics test including the Maternal Haplo test which showed that she was part of the H1c group and therefore came from eastern Europe. We want to know more about her ancestors and genealogy. Given that I have already done a DNA test, what might you advise as to the best avenue to take. Thank you, Nicola

    • Marc McDermott

      Hi Nicola. I haven’t tried CRI Genetics so I don’t know what/if you can do with the raw DNA data. I would check with both MyHeritage and FamilyTreeDNA (and even gedmatch) to see if they accept raw data uploads from CRI. You need to be in a large database where you can potentially find living cousins in order to see how you fit in their family trees. Then with a bit of research, you can deduce who your mother’s parents were. If you cannot upload your data anywhere and you have the budget, I would strongly recommend you test again with ancestry.

      • Nicola Bowie

        Thanks so much for your advice Marc. I will give it a try. Very best wishes,
        Nicola

  8. Jennifer

    Hello, I am the A-typical American Heinz 57.
    Irish, Scottish, Welsh, Italian.
    All I want is a break down of how much of this-that-and the other I am.
    Not interested in a family tree or finding distant relatives to connect with.

    • Marc McDermott

      Go with Ancestry or MyHeritage.

  9. Jayson Harvey

    Hi Marc, thank you so much for posting this information. My wife and I adopted our daughter but she actually my niece as my half-sister was her birth mother. I have used My Heritage to get info, my sister has not as far as I know. I obviously have contact with my sister but the birth father is not present and all I know about him is that he is from Mexico. I would like to be able to give some information to my daughter down the line as she would be the only member of our family with Mexican heritage. What would be the best test to use on her and should I get a test for my sister as well?

    • Marc McDermott

      Hi Jayson. What type of information are you looking for? Family tree and ancestors or just ethnicity?

  10. rachel

    I was adopted back in the 1980’s. I have no information about either of my biological parents and my adoption was a closed one. I am wanting to find out health information as well as possibly finding out if I have any siblings. Since I know nothing, where should I start? What would be the best test or tests to give me an idea/ possibly find relatives and “open” pandoras box so to speak? Thanks!

    • Marc McDermott

      Hi Rachel. Your best bet will be the Ancestry Health test which also includes the standard ancestry test where you can find relatives. To expand your reach of living cousins, you can transfer your raw DNA from ancestry to myheritage once you get the results.

  11. Allison

    Hi, I’m fairly new to genealogy but my main concern is do you get names, l know the last name we’ve been using as our family name for the last four or five generations isn’t correct and would love to find out who we really are, is that possible?, and on my mother’s side the family is basically instinct, mostly females and no family name, surely there are relatives living, we don’t know them, will we be able to know who they are?

    • Marc McDermott

      A DNA test is a good start, but you’ll need to learn more about genealogy research.

  12. Robert Stack

    I was adopted with no living adopted parents. I know my maternal lineage. I do not know my father’s name, only that he was an American Serviceman. If I take a y-111 test, will names of relatives, be reported in the results?

    • Marc McDermott

      Your best bet would be an autosomal DNA test at ancestry. Then with a bit of research, you can find extended family members on your paternal line which may lead you to your birth father.

  13. Juli Crane

    I don’t see CRI Genetics included in this list. Is there a reason for that? How does that company compare?

    • Marc McDermott

      I have not tested with this company since they aren’t a big player in the genealogical community. That may change at some point.

  14. Greg EW

    I think you should add “privacy policy” to your criteria. These are increasingly a concern to people, and they, in conjunction with the provider’s “Terms of Service” are as, or more, difficult to understand than the various types of DNA testing!

    • Marc McDermott

      That’s a good point, thanks Greg. I’ll look into adding that.

      • Sharon Morris

        Great job. The same here if I knew who had access to my information without trawling through every provider’s terms and conditions, my extended family and I would have done ours long ago.

  15. Debbie

    I would love to know how my grandparents ended in the regions they did, and would love to trace back to overseas family

  16. Antonio Bestard

    I want to know if my older brother is related to me. I now have ordered two(2) DNA kits for he and I to take. I am interested to find out if he is related. How do I go about asking this specific question to 23 & M

    • Marc McDermott

      As long as you both take an autosomal test with the same company, they will tell you when you get the results.

  17. Janet Dixon

    Hi there, interesting info – thanks. You missed out on a very important point though, 23&Me also checks for Neanderthal pointers, which other sites do not appear to do… cheers

  18. P. J.

    Hi Mark, there’s some evidence that my mother’s family were Gypsies. Is it possible that DNA from these Roma/Gypsy ancestors would show up in anything other than mtDNA because Gypsies are a “founder population”?

    • Marc McDermott

      I don’t think a DNA would pick up on this – sorry to say.

  19. Bob

    Update on 23&Me, their database has now reach 10 Million.

    • Marc McDermott

      Thanks, Bob. I updated the page to reflect this.

  20. Nuno Antunes

    Hey Mark, what would you recommend to find relatives for a Portuguese family?
    I know my relatives are Portuguese until the 4th generation but have no clue for the rest.
    I know ancestry has the biggest database, but MyHeritage has a good international database.
    Which one do you recommend?
    thank you!
    Nuno

    • Marc McDermott

      I would test with Ancestry, then upload your raw dna to MyHeritage for a small fee. This way you get into both databases and is much cheaper than testing with both.

Leave a Reply to Bernadette Yeager Cancel reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.